An inverse model for calculation of global volume transport from wind and hydrographic data

The P-vector inverse method has been successfully used to invert the absolute velocity from hydrographic data for the extra-equatorial hemispheres, but not for the equatorial region since it is based on the geostrophic balance. A smooth interpolation scheme across the equator is developed in this study to bring together the two already known solutions (P-vectors) for the extra-equatorial hemispheres. This model contains four major components: (a) the P-vector inverse model to obtain the solutions for the two extra-equatorial hemispheres, (b) the objective method to determine the Ψ-values at individual islands, (c) the Poisson equation-solver to obtain the Π-values over the equatorial region from the volume transport vorticity equation, and (d) the Poisson equation-solver to obtain the Ψ and depth-integrated velocity field (U, V) over the globe from the Poisson Ψ-equation. The Poisson equation-solver is similar to the box model developed by Wunsch. Thus, this method combines the strength from both box and P-vector models. The calculated depth-integrated velocity and Ψ-field agree well with earlier studies.     

C4ISR系统信息质量对作战效果的影响分析

明确C4ISR系统信息质量对作战效果的影响是当前研究的热点与前沿问题。在介绍信息质量相关概念的基础上,研究C4ISR系统信息在物理域、信息域和认知域的转换过程以及转换过程中的信息质量度量方法。以对抗双方作战单位剩余数量为作战效果度量指标,从信息质量的完整性、正确性和精确性的指标入手,构建单兵种对单兵种条件下和多兵种对多兵种条件下的Lanchester方程,给出一般条件下的求解方法,由此形成C4ISR系统信息质量对作战效果的影响分析方法框架。     

塑性极限分析上限法在边坡安全系数求解中的应用

基于塑性极限分析上限法在边坡中建立一个合理的速度场,取滑动面为对数螺旋曲面,分别求得边坡滑动体、外荷载所做外功率和滑动面上内能消散率的计算表达式.然后定义材料强度储备安全系数为边坡的稳定安全系数,即边坡中岩土体的c和φ按同一比例折减后边坡达到极限平衡状态,由此可求得边坡处于极限状态时的外功率与内能消散率.再结合虚功率方程得出边坡安全系数的表达式,进而求得其最小上限解,便能确定边坡最不利滑动面的位置以及其最小安全系数.最后,以一个边坡安全系数求解为算例,把本文的计算结果与多种传统方法的计算结果比较,证明本文所提出的方法合理可行.     

吊弦振动频率及幅度对疲劳寿命的影响分析

推导吊弦的振动方程,用数值方法求解振动方程,模拟位移,横截面作用力和弯矩的动态变化规律。根据吊弦的应力时程、利用MATLAB数值计算程序分析影响吊弦疲劳寿命的因素(如振幅和频率)。数值计算结果表明:吊弦疲劳寿命的对数值随着频率和振幅的增加呈现出线性降低的趋势。     

漩门湾水域波浪计算分析

对漩门湾水域的波浪进行分析研究,利用波浪传播变形数值计算模式对该水域的波浪场作了推算,得出工程水域的波高分布,同时得出了防波堤的设计波浪,为围垦工程围堤设计提出科学依据。     

悬索桥主缆温度场计算

研究目的:精确地计算悬索桥主缆各种状态下的温度场,对于悬索桥的架设至关重要.为此,在一些基本假设的基础上,建立主缆的热分析模型和非稳态热传导微分方程,推导太阳热辐射和热对流边界条件,主缆计算模型的热物性参数则采用了模型试验得到的结果.为了得到特定环境条件下的数值解,建立主缆温度场的计算方法及主缆热平衡矩阵方程.研究结论:通过对某桥梁主缆温度场的有限元计算及与实桥主缆温度场实测结果的对比,证明了计算方法的精确和可靠,可用于悬索桥主缆设计、施工和运营阶段的温度场计算.     

泛函方程中Φ(ω(x))=ω'(x)Φ(x)的可微解问题

本文研究泛函方程Φ(ω(x))=ω'(x)Φ(x),证明了 C~(r)(r≥1)可微解的存在性定理,同时给出解的构造。     

方程求根的Hermite抛物插值法

本文提出了方程求实根的一个 Hermite 抛物插值法,并论证了它的收敛性,敛速为1+2~(1/2)阶.若所求根为二重根(重数未知),则敛速为1/2+(3(1/2))/2阶.若将所得公式与牛顿求根公式复合,则有5阶的敛速;若所求根为二重根,则复合法有1.5阶的敛速.     

Car sharing in Norwegian urban areas: Examining interest,intention and the decision to enrol

This article’s objective is to investigate the effects of sociodemographic and residential built environments, directly and indirectly through personality traits, attitudes and car ownership, on willingness to use car sharing in the case of Norway. This is done by examining multiple dimensions of the adoption process: the stated general interest and intention to participate in car sharing among non-members, as well as the decision to enrol as a car sharing user by comparing members to non-members. In this study, we analyse web survey data from 2414 residents from urban areas in Norway, using three structural equation models. Our findings indicate that the adoption of car sharing is complexly related to car ownership, with a noteworthy discrepancy indicating greater car sharing interest, but lower car sharing membership rates among car owners. We also find that environmental concerns exert a clear positive effect on all three dimensions of the adoption process. Being careful with money is linked negatively to interest and intention to participate, while being sociable and agreeable exerts no effect. Car sharers’ sociodemographic profiles are typically that of early adopters, but many of the effects, especially on interest, are mediated by car ownership, environmental consciousness and/or being careful with money, rather than directly on the sociodemographic profiles. Finally, we find car sharing to be more prominent in denser areas, but we did not discover a clear connection with access to public transport.     

飞机在双面横坡跑道上的航向稳定性

分析了飞机在双面横坡机场跑道上的受力情况, 通过建立飞机在双面横坡上的运动方程, 得出了飞机航向稳定性与机场双面横坡跑道坡度值的关系。结果表明横坡对航向稳定性有一定的影响, 在现行规范取值时, 影响非常有限。结论可用于指导机场跑道的横坡设计。